During the last few decades substantial effort has been expanded in developing folding systems for providing improved automation in handling and processing large volumes of repetitively produced printed material. In particular, industries, such as utilities, repeatedly produce and distribute large volumes or runs of monthly bills or statements which must be inserted in envelopes, sealed and mailed. In addition, numerous other businesses have similar large printing requirements for monthly distribution of invoices, checks, and the like. Furthermore, many business organizations distribute large quantities of pre-printed letters, advertisements, and the like, all of which must be folded inserted in envelopes and mailed.
In spite of the expanding demand for folding systems which would reduce the manual labor involved in handling these large volume production runs of printed material, no folding systems have been achieved which are capable of fully satisfying all of the needs and the demands of these different industries. In particular, no prior art system has achieved a universally applicable folding and sealing system capable of receiving pre-printed sheets of material having adhesive zones and folding the sheets of material into a configuration which produces a final product which emulates a conventional envelope. At best, some prior art systems have achieved folding systems for capturing material therein. However, these prior art systems produce sealed envelope-shaped products which are incapable of visually simulating a conventional envelope and typically incorporate opening strips which are difficult for consumers to use in order to gain access to the contents of the envelope.
In a typical prior art system, the folding apparatus places two folds in a sheet of paper. In order to place the first fold in the sheet of paper, the sheet is fed in from a paper source through a pair of feed rollers into a first chute. The sheet advances until it contacts a first sheet stop. As the midsection of the sheet continues to advance, the sheet buckles away from the first chute. The buckle then comes into contact with and is fed through a pair of intermediate rollers which fold the sheet at the buckle.
To place a second fold in the sheet of paper, the sheet is advanced from the intermediate pair of rollers into a second chute. The paper advances until it contacts a second sheet stop. As the midsection of the sheet continues to advance, the sheet buckles away from the second chute. The buckled portion of the sheet then comes into contact with and is fed through a pair of exit rollers which fold the sheet at the second buckle. Typically, one of the feed rollers and one of the exit rollers form the intermediate pair of rollers. Thus, the folding apparatus requires a total of four rollers.
If it is desired to seal the folded sheet of paper, that is, bond the sheet of paper to itself such that the sheet cannot readily be unfolded without breaking the bond, the sheet of paper is subsequently advanced through a set of sealing rollers. The sealing rollers compress the folded sheet such that an adhesive positioned on the sheet can seal the folded sheet of paper. The adhesive can either be heat activated, which requires the sheet to be heated by a heating element prior to being advanced through the sealing rollers. Alternately, the adhesive can be pressure sensitive which requires that the sealing rollers exert a high pressure on the folded sheet of paper as it passes through the sealing rollers.
A problem with folder and sealing apparatus heretofore designed is that the sealing rollers add cost and complexity to the folding apparatus as well as increasing the size of the folding apparatus. In addition to the two sealing rollers, a heating unit must be employed to activate heat activated adhesive. Alternately, a biasing device must be employed to supply the force necessary to activate pressure sensitive adhesives. In addition, the sealing rollers must be driven either by the motor that rotates the other rollers, or by a separate motor. In either case, a larger motor or an additional motor as well as the additional components undesirably increases the cost and size of the folding apparatus.
In addition, the pressure required to bond the sheet of paper to itself using pressure sensitive adhesives can be quite high, thus necessitating that a large force be maintained between the two sealing roller. This large force increases the rolling resistance between the sealing rollers which increases the amount of power required to operate the sealing rollers. Thus, the large sealing force requires a relatively large and expensive motor and power supply.
Therefore, it is a principal object of the present invention to provide a fully integrated system for receiving pre-printed sheets and folding and sealing the sheets into an envelope configuration.
Another object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which requires a minimum number of components and employs low power, an inexpensive motor, and smaller power supply.
A further object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which has a new and useful construction for folding and sealing sheets of paper and produces securely folded and sealed final products.
Another object of the present invention to is to provide a sheet folding and sealing system having the characteristic features described above which is relatively inexpensive to manufacture.
Another object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which is durable.
A further object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which is capable of long-term continuous use without manual intervention.
Another object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which smaller in size.
Another object of the present invention is to provide a sheet folding and sealing system having the characteristic features described above which does not require a relatively large and expensive motor and power supply.
Other and more specific objects of the present invention will become apparent from the following description and attached drawings.